Loin puller with two separate cutting blades

ABSTRACT

Disclosed is a loin puller for trimming off the backfat of a loin that has been scribed from a belly. This loin puller has a frame on which is mounted a conveying system for engaging the loin and moving it towards a cutting zone. In this zone, a cutting tool is mounted for engaging the loin when it is moved by the conveying system, and for cutting the backfat to be trimmed off from the loin, with the so-cut backfat remaining attached to the belly. The cutting tool has two blades that are preferably controlled independently from each other. One of these blades is arcuate and positioned onto the frame so as to engage at least one part of the loin from a side of the loin opposite to the belly, and to cut the backfat to be trimmed from the loin. The other blade is L-shaped and positioned onto the frame so as to engage another part of the loin and cut the backfat to be trimmed thereof directly from the scribing line just below the back ribs of the loin. Both of the blades are long enough so as to ensure that all the backfat of the loin be trimmed off. Advantageously, a plate actuated by a piston is pivotably mounted about a vertical axis in front of the L-shaped blade so as to engage into the scribing line of the loin to be trimmed and push the backribs of the loin laterally away just before the loin reaches the cutting tool.

CROSS-REFERENCE

The present application is a continuation-in-part of application Ser.No. 11/074.795 filed on Mar. 9, 2005 with the benefit of the priority ofCanadian patent application No. 2,460,547 filed on Mar. 10, 2004.

FIELD OF THE INVENTION

The present invention relates to a loin puller of improved structure,which comprises a cutting tool having two blades instead of one only, inorder to trim off the backfat from a loin while leaving the so cutbackfat attached to the belly.

BACKGROUND OF THE INVENTION

Loin pullers are well known machines used in the meat processingindustry for trimming off the backfat of a loin, in particular a porkloin.

As shown in FIG. 1 of the accompanying drawings, the central part or“middle” of the carcass-half of a piece of meat comprises two main partsrespectively called “loin” and “belly”. The loin is adjacent to the cutportion of the spinal column. The front portion of the loin containsribs which are called “back ribs”. The belly which is also called“flank”, is a part which is adjacent to the loin at the opposite of thespinal column. The ends of the ribs which extend along the belly canaltogether be separated from the same to form “spare ribs”, or they canbe removed individually. After removal of the ribs, the belly is mainlyused to prepare bacon. The whole carcass-half is covered by an externallayer of fat which extends under the loin and belly. The thickness ofthis layer of fat depends on several parameters including, inter alia,the size, the origin and the nutrition of the animal. This fat is theone that can be found in bacon. Therefore, it is important from apractical standpoint to keep a proper amount of fat with the belly priorto cutting the same. However, it is important to remove some of the fatextending under the loin to avoid an over load of fat in the finalproduct and have to call for an extra manpower or a complementaryequipment to remove this fat if it has not been removed from the loin inthe loin puller.

Prior to processing a loin in a loin puller, it is of course necessaryto separate it from the belly. So far, there have been two differentmethods of doing so.

The first method, called “Canadian cut”, consists in completelyseparating the belly from the loin by completely cutting thecarcass-half according to a suitable cutting line which may varydepending on the need. An example of such a cutting line is shown indotted lines in FIG. 1. Such a cutting can be carried out eithermanually or by means of another machine located upstream the loin pulleror within the same. Once separated, the belly can be directed towardsanother machine or another working table specially adapted for thispurpose, in order to separate the spare ribs. On the other hand, theloin is introduced into the loin puller, in order to trim off its fat.

As a non-limitative example of a loin puller especially adapted toprocess loins after full separation from the adjacent bellies, referencecan be made to U.S. Pat. No. 5,090,939 issued on Feb. 25, 1992 in thename of the Applicant, G.E. LEBLANC INC.

The second method, called “American cut”, consists in cutting (scribing)only the internal part of the carcass-half, that is the upper part ofthe carcass-half shown in FIG. 1, following the same type of cuttingline as above, except for the fat. As a result, the layer of fat remainsuncut and maintains altogether the loin and the belly. Then, both ofthem may be transferred together to a working table where the loin isseparated from the belly while leaving some of the loin fat attached tothe belly. The main advantage of this method is that it makes itpossible to recover part of the fat and meat of the loin together withthe belly, which part would otherwise have been left onto the loin andtrimmed off by a cutting blade. Usually, this method of processingcarcass-halves is carried out manually, even though industrial machineshave been proposed to do it.

As a non-limitative example of a loin puller adapted to process loinsnot fully separated from the adjacent bellies, reference can be made toU.S. Pat. No. 6,336,856 issued on Jan. 8, 2002 also in the name of G.E.LEBLANC INC.

In all the existing loin pullers whatever be their kinds of cut, viz.Canadian or American ones, it is of common practice to use an arcuatecutting blade mounted above the loin conveying system in order to engagethe loin while the same is moved forwards, and to cut the layer of fatto be trimmed off from the same, with or without lean meat on thetrimmed fat attached to the belly. The arcuate cutting blade is ofcourse “associated” to a control system whose purpose is to adjust theheight and curvature of the blade as a function of the size, shape andother characteristics of the loin to be processed, especially thethickness of the layer of fat to be trimmed off. This control system canbe operated manually or it can be operated by an automatic measurementsystem which evaluates the main parameters required for adjusting thecutting blade as a function of the evaluation of the main parametersfrom trimming off the loin. For further details on this kind ofautomation, reference can be made by way of non-restrictive examples tothe description of the above mentioned U.S. Pat. No. 5,090,939.

In order to maximize yields on bellies as compared to what is achievedwhen use is made of a conventional arcuate cutting blade, it has alreadybeen suggested to use an arcuate cutting blade having a distortedportion (also called “inwardly projecting bend” or “indented bight”) onone of its sides. In this connection, reference can be made to the abovementioned U.S. Pat. No. 6,336,856 to G.E. LEBLANC INC., as well as toU.S. Pat. No. 6,155,919 issued on Dec. 5, 2000 to SWIFT & CO. and U.S.Pat. No. 6,089,968 issued on Jul. 18, 2000 to ACRALOC CORP. Referencecan also be made to U.S. Pat. No. 6,547,658 issued on Apr. 15, 2003 toACRALOC CORP., which discloses a loin puller comprising two bladesextending vertically within the conveyor, one of said blades beingZ-shaped to fully separate the loin from the belly while leaving leanfingers on the belly to increase the exposed amount of lean meat on thebackfat side of the belly, the other one of said blades being J-shapedto trim off the fat and skin from the loin after it has been separatedfrom the belly.

In all above-mentioned cases, the utility and advantage of the distortedportion of the blade is to allow trimming off of the loin close to theribs while leaving lean fingers of meat on the belly.

It is worth noting however that there is a basic difference between theway the arcuate cutting blade with a distorted portion disclosed in G.E.LEBLANC's U.S. Pat. No. 6,336,856 is used and the way the bladedisclosed in the three other patents mentioned hereinabove, is used. InG.E. LEBLANC's U.S. Pat. No. 6,336,856, the arcuate cutting blade isexclusively used to trim off the fat and skin (also called “backfat”)from the back of the loin while simultaneously leaving fingers of meaton the belly. The arcuate cutting blade separates the loin from thecentral part of the carcass half but it does not separate the fat andskin trimmed off from the loin from the adjacent belly. In fullcontrast, in SWIFT & CO's U.S. Pat. No. 6,155,919 and ACRALOC CORP.'sU.S. Pat. Nos. 6,089,968 and 6,547,658, the arcuate cutting blade(s) is(are) used to fully separate not only the loin itself but also its fatand skin from the belly while leaving fingers of meat on the same. InU.S. Pat. Nos. 6,155,919 and 6,089,968, a single cutter blade is usedjust to separate the loin from the belly while leaving the skin and fatintact on the back of the loin (see and compare FIGS. 2 and 3 of U.S.Pat. No. 6,155,919 and FIGS. 18 and 19 of U.S. Pat. No. 6,089,968 andthe corresponding parts of their specification). In U.S. Pat. No.6,547,658, another blade is used to trim off the fat and skin from theloin. However, even if the fat and skin are trimmed off from the loin,the fat and skin are also separated from the belly either at the sametime or just before.

If arcuate cutting blades with a distorted portion are interesting forthe above mentioned reason, they have the drawback of being verydifficult to make in one piece with an appropriate and efficientsharpened edge. Thus, in practice, the requested cutting especiallyclose to the ribs without risk of hitting them and also hitting theblade bone, is quite difficult to be achieved with good results,especially in the case where, like in G.E. LEBLANC's loin puller, thearcuate part of the cutting blade is mainly used to separate the loinfrom the belly while trimming off the fat and skin from the loin andleaving them attached to the adjacent belly.

SUMMARY OF THE INVENTION

It has now been found that one may solve the above mentioned problemencountered in a loin puller when use is made of an arcuate cuttingblade having a distorted portion, if use is actually made of anothercutting blade separate from the arcuate cutting blade for the purpose ofcutting the loin close to the ribs to leave lean fingers of meat on thebelly prior to further processing the loin to trim off the fat and skin(also called “backfat”) from its back while leaving them attached to theadjacent belly.

It has also been found that an improved efficiency of the cutting isachieved if use is also made of means for pushing laterally away thebackribs that extend in the front of the loin just before said loinreaches the cutting tool, in order to prevent said backribs from hittingthe cutting blade(s).

Thus, the invention is directed to an improved loin puller for trimmingoff the backfat of a loin that has been scribed from a belly along ascribing line, the loin comprising backribs adjacent to the scribingline. This improved loin puller, basically comprises:

-   -   a frame;    -   a conveying system mounted onto the frame for engaging the loin        and moving it towards a cutting zone; and    -   a cutting tool mounted onto the frame in the cutting zone for        engaging the loin when said loin is moved by the conveying        system and for cutting the backfat to be trimmed off from the        loin, with the so-cut backfat remaining attached to the belly,

In accordance with the invention, the cutting tool comprises two blades,one of these blades being arcuate and positioned onto the frame so as toengage at least one part of the loin from a side of the loin opposite tothe belly, and cut the backfat to be trimmed from this part, the otherone of these blades being L-shaped and positioned onto the frame so asto engage another part of the loin and cut the backfat to be trimmedthereof directly from the scribing line just below the back ribs of theloin.

Advantageously also means are positioned in front of the L-shaped bladefor pushing laterally away the backribs extending in the front of theloin just before the loin reaches the cutting tool in order to preventsaid backribs from hitting the L-shaped blade.

As may be appreciated, the invention is thus directed to an independentdual blade loin puller that is devised to keep the backfat portion ofthe loin intact and attached to the belly after the loin has beenseparated.

The invention also makes use of the above mentioned means for pushingthe backribs in the front of the loin to prevent damages on the tips ofthe backribs by the L-shaped blade, which means preferably comprises:

-   -   a plate pivotably mounted about a vertical axis on a support        that extends in front of the L-shaped blade so as to engage into        the scribing line of the loin to be trimmed,    -   a piston connected to the plate so as to make it pivot laterally        toward the loin when the same approaches the cutting zone and        thus push laterally away the backribs that extend in the front        of the loin just before the loin reaches the cutting tool; and    -   an automatic control system for actuating the piston to make the        plate to pivot as disclosed above as soon as the front of the        loin is adjacent to said plate, and then to return said plate        back in original position as soon as the front of the loin has        passed over said plate.

The capability of keeping the backfat attached to the belly portionafter separation of the loin is very important for getting the maximalyields from the three parts of the middle, namely the belly, the loinand the backfat. In practice, the separation line between the belly andthe backfat is depending on multiple belly criteria which can beevaluated only after removing the loin, such as thickness, width, leanmeat content, width and length of the fingers, commercial needs of thebelly market, etc. . . . This evaluation is usually done by trimmeroperators or by new technologies such as automatic belly trimmingprocess.

As described in the prior art except U.S. Pat. No. 6,336,856, theseparation of the backfat and belly is done in the loin puller by oneblade or by one or two of a set of dual blades. Consequently, thisseparation is done following a predetermined width which is always atthe same distance of the scribe line whatever be the characteristics ofthe belly. Such may of course substantially affect the yield of bothproducts because the belly which has been separated from the backfatwill have to be trimmed another time after evaluation of all thecriteria described above and its yield will be lowered if the loinpuller has removed from the belly too much fatback portion or notenough.

Thus, the backfat portions could be too narrow or too wide, therebyaffecting the integrity and value of this product.

Of course, in the improved loin puller according to the invention, bothof the blades have to be long enough to ensure that all the backfat ofthe loin be trimmed off.

Advantageously, two independent control systems may be used foradjusting the respective positions of the blades independently from eachother. These control systems may be operated by an automatic measurementsystem which preferably comprises:

-   -   a roller mounted onto an arm that extends vertically over the        conveying system so as to contact the loin close to the scribing        line and thus permit to determine the thickness of the loin; or    -   a laser beam that projects downwardly from the frame onto the        loin close to the scribing line so as to determine the thickness        of this loin; or    -   an ultrasonic system that projects downwardly from the frame        onto the loin close to the scribing line so as to determine the        thickness of the loin.

To improve the cutting, use is preferably made of an L-shaped blade thathas a vertical portion with a front cutting edge that extends at anangle downwardly rearwardly, and a horizontal position with a frontcutting edge of triangular shape that extends frontwardly towards theloin that is moved by the conveying system. Advantageously, the cuttingedge of the L-shaped blade may also be sharpened more on one side. Inthis connection, it has surprisingly been found that if use is made ofan L-shaped blade having its cutting edge sharpened at an angle more onone side instead of having it sharpened evenly on both sides, muchbetter engagement of the blade in the loin close to ribs may be achievedwithout hitting said ribs or any part of the shoulder blade that couldstill be in the piece of meat, especially when this piece is made ofsoft meat. Moreover, much better results may be obtained.

To improve the cutting and make easier the maintenance of the blades,use is preferably made also of an arcuate cutting blade that has a frontgroove in which is detachably inserted a foldable piece of metal havinga front sharpened cutting edge. Such a piece may be replaced in a fastand easy manner whenever necessary.

Preferably, the L-shaped blade extends in front of the arcuate blade inorder to cut part of the loin close to where it has been scribed, beforethe arcuate blade engages the loin. In this particular case, the arcuateblade that extends behind the L-shaped blade may have two opposite endsconnected to the frame and be shaped so as to engage the loin and cutthe backfat to be trimmed thereof between the side of the loin oppositethe belly and the scribing line. Alternatively and preferably also, thearcuate blade that extends behind the L-shaped blade, has only one endconnected to the frame, and another free end that extends close to theL-shaped blade.

In accordance with a particularly preferred embodiment of the invention:

-   -   the L-shaped blade extends upstream of the arcuate blade in        order to cut part of the loin close to where it has been        scribed, before the arcuate blade engages said loin;    -   the arcuate blade that extends behind the L-shaped blade, has        one end connected to the frame and another end that is free and        extends close to the L-shaped blade;    -   the free end of the arcuate blade is pivotably connected to a        pin that projects horizontally rearwardly from the L-shaped        blade; and    -   the arcuate blade is flexible and the L-shaped blade is rigid.

With this particular embodiment, respective adjustments of the arcuateblade and of the L-shaped blade by their respective control systemspermit to modify the arcuate shape of the arcuate blade and thus toadapt its cutting to the loin to be trimmed off, thereby reducing therisk of scoring the loin portion.

The invention and its advantages will be better understood upon readingthe following non-restrictive description of a preferred embodimentthereof made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a carcass-half showing the main parts ofit, as they have been disclosed hereinabove in the “Background of theinvention”.

FIG. 2 is a rear, left-hand side perspective view of the cutting zone ofan improved loin puller according to a preferred embodiment of theinvention.

FIG. 3 is a front right-hand side perspective view of the two blades ofthe cutting tool of an improved loin puller according to anotherpreferred embodiment of the invention;

FIG. 4 is a rear view of the cutting zone of the improved loin pullershown in FIG. 3, illustrating the respective positions of the blades ofthe cutting tool, when these blades engage the loin and belly;

FIG. 5 is a rear, left-hand side perspective view of the cutting zone ofan improved loin puller according to a further preferred embodiment ofthe invention;

FIG. 6 is a rear view similar to the one shown in FIG. 4, illustratingstill another preferred embodiment of the invention; and

FIGS. 7 a to 7 f are schematic rear views of the blades of the improvedloin puller shown in FIGS. 3 and 4, which Figures illustrate thedistortions that can be given to the arcuate blade of the loin pullerwhen this blade is flexible and operatively connected to the L-shapedblade which is rigid;

FIG. 8 is a left-hand side view of the front part of the cutting zone ofan improved loin puller according to the invention, which show the meanspositioned in front of the L-shaped blade for pushing laterally away thebackribs extending in the front of the loin just before the loin reachesthe cutting tool in order to prevent these backribs from hitting theL-shaped blade; and

FIGS. 9 a to 9 c are front elevation views of the front part of thecutting zone shown in FIG. 8, illustrating the way the plate at thefront of the pushing means is actuated.

DETAILED DESCRIPTION OF THE INVENTION

The improved loin puller 1 according to the preferred embodiment of theinvention as shown in FIGS. 2 to 6, is devised for trimming off the fatand skin viz. the “backfat”, from the back of a loin “L” scribed from abelly “B”, as shown in FIG. 1. This improved loin puller 1 basicallycomprises:

-   -   a frame 3;    -   a conveying system 5 mounted onto the frame for engaging the        loin and moving it towards a cutting zone in the direction shown        by the arrow “A” in the drawings; and    -   a cutting tool mounted onto the frame 3 in the cutting zone for        engaging the loin when the same is moved by the conveying system        5 and for cutting the backfat to be trimmed off from the same        with the so cut backfat still remaining attached to the adjacent        part of the belly, as is shown in FIGS. 4 and 6

As aforesaid, an improvement essentially lies in that the cutting toolcomprises two blades 7 and 9. One of these blades, namely the onenumbered 7, is arcuate and positioned onto the frame 3 so as to engageat least one part of the loin “L” from the side of the loin that isopposite to the belly “B” and to cut backfat to be trimmed off from thispart.

The other one of the blades, namely the one numbered 9, is L-shaped andpositioned onto the frame, so as to engage another part of the loin “L”and cut the backfat to be trimmed thereof directly from the scribingline just below the back ribs “R” of the loin (see FIGS. 4 and 6).

Of course, both of the blades (7, 9) must be long enough so as to ensurethat, as a result of the cuts, they respectively make in the loin “L”all the backfat of the loin be trimmed off.

In accordance with a particularly preferred embodiment of the inventionshown in FIGS. 4 and 6, two independent systems 23, 25 may be used foradjusting the respective positions of the arcuate blade 7 and of theL-shaped blade 11 independently from each other. These two controlsystems 23, 25 can be operated by an automatic measurement system, as isof common practice in the existing automatic loin pullers (see again theU.S. patents cited in the “Background of the invention”). As automaticmeasurement system, use can be made of a system as shown in FIG. 4,which comprises a roller 27 mounted onto an arm 29 that extendsvertically over the conveying system 5 so as to contact the loin closeto the scribing line and thus permit to determine the thickness of thisloin. Alternatively, use can be made of a system as shown in FIG. 6,which comprises a laser beam or an ultrasonic system that projectsdownwardly from the frame onto the loin close to the scribing line so asto determine the thickness of the loin.

In the preferred embodiments shown in FIGS. 2 to 6, the L-shaped blade 9extends upstream of the arcuate blade 7 in order to cut the loin closeto where it has been scribed, before the arcuate blade 7 engages theloin and complete full cutting of the same. It is worth noting howeverthat the blades 7 and 9 could alternatively extend both in a same planetransversal to the conveying system, if such is desired.

As shown in FIG. 6, the arcuate blade 7 that extends behind the L-shapedblade 9 may have two opposite ends 13, 15 that are both connected to theframe. In this particular embodiment, the arcuate blade 7 must of coursebe shaped so as to engage the loin and cut the backfat to be trimmedthereof from the side of the loin that is opposite the belly up to thescribing line.

Alternatively, as shown in FIGS. 2 to 5, the arcuate blade 7 thatextends behind the L-shaped blade 9 may have only one of its ends 13connected to the frame and the other end 15 that remains free andextends close to the L-shaped blade 7. In such a case, the two blades 7and 9 can be completely separate from each other as shown in FIG. 5 oralternatively and preferably, they can be connected to each other:

-   -   either by means of a ring 10 to form a slide, as is shown in        FIG. 2;    -   or by means of a joint of conventional structure, like a string        or a swivel;    -   or even more preferably, by means of a pivot 11 that projects        rearwardly from the L-shaped blade 9, and in which is pivotably        inserted the end of the arcuate blade, as is shown in FIGS. 3        and 4.

Such a connection of the free end of the arcuate blade 7 to the L-shapedblade 9, is particularly interesting in that it makes it possible forthe arcuate blade 7 to be made of a flexible material and be operativelyconnected to the L-shaped blade 9 that is then made of a rigid material.In this particular embodiment, respective adjustments of the arcuateblade and of the L-shaped blade by their own control systems permit tomodify the arcuate shape of the arcuate blade and thus to adapt itscutting to the loin to be trimmed off. Such is illustrated in FIGS. 7 ato 7 f, which show the particular portions of both blades and thecurvature of the arcuate blade 7 as a function of the positions of theircontrol systems 23, 25. In these figures, some of the arrows show themotions given to both of the control systems, up, down or stationary.Other arrows show the way the arcuate blade 7 is flexed as a function ofthe motions of the control systems.

As may thus be noticed, the improved loin puller according to theinvention permits to process loins of any size and/or fatness with amaximum efficiency to properly separate the backfat thereof whatever bethe thickness of such a backfat, while substantially reducing the riskof the scoring portions of the loin without separating the backfat fromthe belly.

As is better shown in FIG. 3, the L-shaped blade 9 preferably has avertical portion with a front cutting edge 17 that extends at an angledownwardly rearwardly, and a horizontal portion with a front cuttingedge 19 of triangular shape that extends frontwardly towards the lointhat is moved by the conveying system.

Advantageously, the cutting edges 17, 19 of the L-shaped blade 9 may besharpened more on one side instead of being sharpened evenly on bothsides like any conventional knife or blade. This “double” arrangement inthe shape and sharpening of the cutting edges 17, 19 of the cuttingblade 9 permits to engage the loin close to the ribs “R” in a moreefficient way while substantially reducing the risk of hitting the ribsor any part of the shoulder blade that would still be in the piece ofmeat. Indeed, as soon as the first rib “R” is lifted up by the cuttingedges of the cutting blade 9 that is sharpened more on one side, theother ribs which are connected to the first one and to each other bypieces of meat will also be lifted up in a smooth manner, therebyreducing the risk of breaking and tearing.

Preferably also, the arcuate blade 7 may have a front groove in which isdetachably inserted a foldable piece of metal 21 having a frontsharpened cutting edge, as shown in FIG. 5. Such makes the maintenanceof the loin puller much easier to assume as one may easily replace thefoldable piece of metal 21 of the blade 7 by another new one.

As disclosed hereinabove, the improved loin puller according to theinvention advantageously comprises also means 41 in front of theL-shaped blade 9 for pushing laterally away the backribs extending inthe front of the loin just before the loin reaches the cutting tool inorder to prevent these backribs from hitting the L-shaped blade anddamaging the very high valve product of the cut.

In the illustrated embodiment shown in FIGS. 8 and 9 a to 9 c, thesemeans 41 comprise a plate 43 that is preferably triangular in shape andis pivotably mounted about a vertical axis 45 on a support 47 thatextends in front of the L-shaped blade 9 so as to engage into thescribing line of the loin to be trimmed. A piston 49 is connected to theplate 43 via an actuating rod 51 so as to make it pivot laterally towardand away from the loin when the same approaches the cutting zone andthus push laterally away the backribs that extend in the front of theloin just before the loin reaches the cutting tool.

Of course, an automatic control system is provided for actuating thepiston 49 to make the plate 43 to pivot as disclosed above and shown inFIG. 9 c as soon as the front of the loin is adjacent to this plate, andthen to return said plate back in original position as shown in FIG. 9 aas soon as the front of the loin has passed over the plate.

As may be noticed, the support 47 is preferably mounted on the frame 3of the loin puller via a set of springs 53 which allows it to move upand down and thus have its lower edge 55 that extends just behind theplate 43 at the same level of it to engage also into the scribing lineand stay in it until the loin reaches the L-shaped blade 9

Tests have been carried out by the Applicant on an improved loin pulleras shown in FIGS. 3 and 4, wherein the arcuate blade 7 was flexible andhad a free end pivotably connected to a pin 11 projecting rearwardlyfrom the L-shaped blade 9. These tests have proved to be particularlyefficient and have clearly demonstrated the advantage of using twoseparate cutting blades as disclosed hereinabove, instead of using onlyone blade, in terms of efficiency, cost and results.

Tests have also been carried out with the means 41 illustrated in FIGS.8 and 9 a to 9 c. They have proved to be very efficient too, the risksfor the backribs of inadvertly hitting the blades by being completelyavoided.

Thus, with the improved loin puller according to the invention, betterand more efficient cutting of the loin may easily be achieved. Inaddition to a better cutting, other advantages are also achieved, suchas easier installation, replacement and maintenance of each blade,especially when each blade has one end only connected to the frame.

Of course, numerous modifications could be made to the improved loinpuller according to the preferred embodiments of the invention asdisclosed hereinabove without departing from the scope of the inventionas claimed hereinafter, it being understood that all the otherstructural features of the loin puller as such are conventional andneeds not be further described.

1. In a loin puller for trimming off the backfat of a loin that has beenscribed from a belly along a scribing line, the loin comprising backribsadjacent to the scribing line, said loin puller comprising: a frame; aconveying system mounted onto the frame for engaging the loin and movingit towards a cutting zone; and a cutting tool mounted onto the frame inthe cutting zone for engaging the loin when said loin is moved by theconveying system and for cutting the backfat to be trimmed off from saidloin, with the so-cut backfat remaining attached to the belly, saidcutting tool comprises two blades, one of said blades being arcuate andpositioned onto the frame so as to engage at least one part of the loinfrom a side of said loin opposite to the belly, and cut the backfat tobe trimmed from said one part, the other one of said blades beingL-shaped and positioned onto the frame so as to engage another part ofthe loin and cut the backfat to be trimmed thereof directly from thescribing line just below the back ribs of said loin, both of said bladesbeing long enough so as to ensure that all the backfat of the loin betrimmed off, the improvement wherein said loin puller further comprises:means positioned in front of the L-shaped blade for pushing laterallyaway the backribs extending in the front of the loin just before saidloin reaches the cutting tool in order to prevent said backribs fromhitting said L-shaped blade.
 2. The improved loin puller of claim 1,wherein said pushing means for pushing the backribs in the front of theloin comprises: a plate pivotably mounted about a vertical axis on asupport that extends in front of the L-shaped blade so as to engage intothe scribing line of the loin to be trimmed, a piston connected to theplate so as to make it pivot laterally toward the loin when the sameapproaches the cutting zone and thus push laterally away the backribsthat extend in the front of the loin just before the loin reaches thecutting tool; and an automatic control system for actuating the pistonto make the plate to pivot as disclosed above as soon as the front ofthe loin is adjacent to said plate, and then to return said plate backin original position as soon as the front of the loin has passed oversaid plate.
 3. The improved loin puller of claim 2, further comprisingtwo independent control systems for adjusting the respective positionsof the blades independently from each other
 4. The improved loin pullerof claim 3, wherein the two control systems are operated by an automaticmeasurement system.
 5. The improved loin puller of claim 4, wherein theautomatic measurement system comprises a roller mounted onto an arm thatextends vertically over the conveying system so as to contact the loinclose to the scribing line and thus permit to determine the thickness ofsaid loin.
 6. The improved loin puller of claim 4, wherein the automaticmeasurement system comprises a laser beam that projects downwardly fromthe frame onto the loin close to the scribing line so as to determinethe thickness of said loin.
 7. The improved loin puller of claim 4,wherein the automatic measurement system comprises an ultrasonic systemthat projects downwardly from the frame onto the loin close to thescribing line so as to determine the thickness of said loin.
 8. Theimproved loin puller of claim 4, wherein the L-shaped blade has avertical portion with a front cutting edge that extends at an angledownwardly rearwardly, and a horizontal portion with a front cuttingedge of triangular shape that extends frontwardly towards the loin thatis moved by the conveying system.
 9. The improved loin puller of claim2, wherein the arcuate cutting blade has a front groove in which isdetachably inserted a foldable piece of metal having a front sharpenedcutting edge.
 10. The improved loin puller of claim 2, wherein theL-shaped blade extends upstream of the arcuate blade in order to cutpart of the loin close to where it has been scribed, before the arcuateblade engages said loin.
 11. The improved loin puller of claim 10,wherein the arcuate blade that extends behind the L-shaped blade, hastwo opposite ends connected to the frame and is shaped so as to engagethe loin and cut the backfat to be trimmed thereof between the side ofsaid loin opposite the belly and the scribing line.
 12. The improvedloin puller of claim 10, wherein the arcuate blade that extends behindthe L-shaped blade, has one end connected to the frame and another endthat extends close to the L-shaped blade.
 13. The improved loin pullerof claim 10, wherein the free end of the arcuate blade is connected tothe L-shaped blade by a joint.
 14. The improved loin puller of claim 10,wherein the free end of the arcuate blade is slideably connected to theL-shaped blade;
 15. The improved loin puller of claim 12, wherein thefree end of the arcuate blade is pivotably connected to a pin thatprojects horizontally rearwardly from the L-shaped blade.
 16. Theimproved loin puller of claim 15, wherein the arcuate blade is flexibleand the L-shaped blade is rigid.
 17. The improved loin puller of claim4, wherein: the L-shaped blade extends upstream of the arcuate blade inorder to cut part of the loin close to where it has been scribed, beforethe arcuate blade engages said loin; the arcuate blade that extendsbehind the L-shaped blade, has one end connected to the frame andanother end that extends close to the L-shaped blade; the free end ofthe arcuate blade is pivotably connected to a pin that projectshorizontally rearwardly from the L-shaped blade; and the arcuate bladeis flexible and the L-shaped blade is rigid; whereby in use, respectiveadjustments of the arcuate blade and of the L-shaped blade by theirrespective control systems permit to modify the arcuate shape of thearcuate blade and thus to adapt its cutting to the loin to be trimmedoff.
 18. The improved loin puller of claim 17, wherein the L-shapedblade has a vertical portion with a front cutting edge that extends atan angle downwardly rearwardly, and a horizontal portion with a frontcutting edge of triangular shape that extends frontwardly towards theloin that is moved by the conveying system.
 19. The improved loin pullerof claim 18, wherein the arcuate cutting blade has a front groove inwhich is detachably inserted a foldable piece of metal having a frontsharpened cutting edge.
 20. The improved loin puller of claim 1,wherein: the L-shaped blade extends upstream of the arcuate blade inorder to cut part of the loin close to where it has been scribed, beforethe arcuate blade engages said loin; the arcuate blade that extendsbehind the L-shaped blade, has one end connected to the frame andanother end that extends close to the L-shaped blade; the free end ofthe arcuate blade is pivotably connected to a pin that projectshorizontally rearwardly from the L-shaped blade; and the arcuate bladeis flexible and the L-shaped blade is rigid; whereby in use, respectiveadjustments of the arcuate blade and of the L-shaped blade by theirrespective control systems permit to modify the arcuate shape of thearcuate blade and thus to adapt its cutting to the loin to be trimmedoff.